test_slice.py 4.5 KB

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  1. # tests for slice objects; in particular the indices method.
  2. import unittest
  3. import weakref
  4. from cPickle import loads, dumps
  5. from test import test_support
  6. import sys
  7. class SliceTest(unittest.TestCase):
  8. def test_constructor(self):
  9. self.assertRaises(TypeError, slice)
  10. self.assertRaises(TypeError, slice, 1, 2, 3, 4)
  11. def test_repr(self):
  12. self.assertEqual(repr(slice(1, 2, 3)), "slice(1, 2, 3)")
  13. def test_hash(self):
  14. # Verify clearing of SF bug #800796
  15. self.assertRaises(TypeError, hash, slice(5))
  16. with self.assertRaises(TypeError):
  17. slice(5).__hash__()
  18. def test_cmp(self):
  19. s1 = slice(1, 2, 3)
  20. s2 = slice(1, 2, 3)
  21. s3 = slice(1, 2, 4)
  22. self.assertEqual(s1, s2)
  23. self.assertNotEqual(s1, s3)
  24. class Exc(Exception):
  25. pass
  26. class BadCmp(object):
  27. def __eq__(self, other):
  28. raise Exc
  29. __hash__ = None # Silence Py3k warning
  30. s1 = slice(BadCmp())
  31. s2 = slice(BadCmp())
  32. self.assertRaises(Exc, cmp, s1, s2)
  33. self.assertEqual(s1, s1)
  34. s1 = slice(1, BadCmp())
  35. s2 = slice(1, BadCmp())
  36. self.assertEqual(s1, s1)
  37. self.assertRaises(Exc, cmp, s1, s2)
  38. s1 = slice(1, 2, BadCmp())
  39. s2 = slice(1, 2, BadCmp())
  40. self.assertEqual(s1, s1)
  41. self.assertRaises(Exc, cmp, s1, s2)
  42. def test_members(self):
  43. s = slice(1)
  44. self.assertEqual(s.start, None)
  45. self.assertEqual(s.stop, 1)
  46. self.assertEqual(s.step, None)
  47. s = slice(1, 2)
  48. self.assertEqual(s.start, 1)
  49. self.assertEqual(s.stop, 2)
  50. self.assertEqual(s.step, None)
  51. s = slice(1, 2, 3)
  52. self.assertEqual(s.start, 1)
  53. self.assertEqual(s.stop, 2)
  54. self.assertEqual(s.step, 3)
  55. class AnyClass:
  56. pass
  57. obj = AnyClass()
  58. s = slice(obj)
  59. self.assertTrue(s.stop is obj)
  60. def test_indices(self):
  61. self.assertEqual(slice(None ).indices(10), (0, 10, 1))
  62. self.assertEqual(slice(None, None, 2).indices(10), (0, 10, 2))
  63. self.assertEqual(slice(1, None, 2).indices(10), (1, 10, 2))
  64. self.assertEqual(slice(None, None, -1).indices(10), (9, -1, -1))
  65. self.assertEqual(slice(None, None, -2).indices(10), (9, -1, -2))
  66. self.assertEqual(slice(3, None, -2).indices(10), (3, -1, -2))
  67. # issue 3004 tests
  68. self.assertEqual(slice(None, -9).indices(10), (0, 1, 1))
  69. self.assertEqual(slice(None, -10).indices(10), (0, 0, 1))
  70. self.assertEqual(slice(None, -11).indices(10), (0, 0, 1))
  71. self.assertEqual(slice(None, -10, -1).indices(10), (9, 0, -1))
  72. self.assertEqual(slice(None, -11, -1).indices(10), (9, -1, -1))
  73. self.assertEqual(slice(None, -12, -1).indices(10), (9, -1, -1))
  74. self.assertEqual(slice(None, 9).indices(10), (0, 9, 1))
  75. self.assertEqual(slice(None, 10).indices(10), (0, 10, 1))
  76. self.assertEqual(slice(None, 11).indices(10), (0, 10, 1))
  77. self.assertEqual(slice(None, 8, -1).indices(10), (9, 8, -1))
  78. self.assertEqual(slice(None, 9, -1).indices(10), (9, 9, -1))
  79. self.assertEqual(slice(None, 10, -1).indices(10), (9, 9, -1))
  80. self.assertEqual(
  81. slice(-100, 100 ).indices(10),
  82. slice(None).indices(10)
  83. )
  84. self.assertEqual(
  85. slice(100, -100, -1).indices(10),
  86. slice(None, None, -1).indices(10)
  87. )
  88. self.assertEqual(slice(-100L, 100L, 2L).indices(10), (0, 10, 2))
  89. self.assertEqual(range(10)[::sys.maxint - 1], [0])
  90. self.assertRaises(OverflowError, slice(None).indices, 1L<<100)
  91. def test_setslice_without_getslice(self):
  92. tmp = []
  93. class X(object):
  94. def __setslice__(self, i, j, k):
  95. tmp.append((i, j, k))
  96. x = X()
  97. with test_support.check_py3k_warnings():
  98. x[1:2] = 42
  99. self.assertEqual(tmp, [(1, 2, 42)])
  100. def test_pickle(self):
  101. s = slice(10, 20, 3)
  102. for protocol in (0,1,2):
  103. t = loads(dumps(s, protocol))
  104. self.assertEqual(s, t)
  105. self.assertEqual(s.indices(15), t.indices(15))
  106. self.assertNotEqual(id(s), id(t))
  107. def test_cycle(self):
  108. class myobj(): pass
  109. o = myobj()
  110. o.s = slice(o)
  111. w = weakref.ref(o)
  112. o = None
  113. test_support.gc_collect()
  114. self.assertIsNone(w())
  115. def test_main():
  116. test_support.run_unittest(SliceTest)
  117. if __name__ == "__main__":
  118. test_main()